Guide bars of this type are provided in power-driven chain saws for guiding and supporting an endless saw chain revolving about the guide bar.
Chain saws of this type intended for portable use are guided and carried by hand when in operation. For this reason, attempts have been made for a long time to reduce the weight of such chain saws as much as possible. Attempts have also been made to reduce the weight of the guide bar, since the guide bar, which for reasons of strength is usually made of steel, contributes considerably to the overall weight of the tool.
In a known chain saw, the guide bar has been designed in a sandwich form for this reason and includes two side parts and an intermediate part disposed therebetween and tightly joined thereto. The side parts extend beyond the intermediate part to form a guide groove for the saw chain. The side parts and intermediate part are made of steel and are joined to each other by spot welds. To reduce the weight, cutouts are provided in the intermediate part, so that the intermediate part substantially comprises a narrow ring which forms the base of the groove. The two sides of the ring are joined by strut-like webs. The function of this intermediate part having the cutouts is to assure accurate spacing between the two side parts, to determine the depth of the groove, and to prevent chips or the like from getting in between the side parts.
This known guide bar has the disadvantage that it is still relatively heavy, especially when the guide bars are long.